Flow around a cylinder is important in the motion of microorganisms found in biological viscoelastic fluids that propel themselves by flagella. Flow around a cylinder experiments are difficult to perform because of the influence of the walls and ends. An approach was developed to measure the drag on a cylinder by correcting for wall and end effects. Cylinders were vertically dipped into fluids in an annular shaped tank, which was rotated to generate a flow. The force acting on a cylinder was measured using a custom force transducer. This method was used for a Newtonian fluid and two Boger fluids. The drag of the Boger fluids was several times that of an equivalent Newtonian fluid. A cavity was observed to develop behind the cylinders once the flow surpassed a critical velocity. Streakline images taken during the experiment confirmed the presence of a wake region behind the cylinders.

Over the last three centuries the rapidly increasing influence of technology has come to dominate every aspect of human life. Progressive realization of adverse effects has led to increasing demand for and imposition of control measures. The concept of common law embodied in legal tradition have been found inadequate, and forced a change to "enacted law". The regulatory explosion necessitated delegation from legislative to executive agencies.The resulting techniques of control developed in the United Kingdom, New Zealand, Australia, Canada and the United States are examined. One common factor stands out, the extensive dependence of law-making bodies on independent technical specification material from non-government sources, and the confused, conflicting, and inconsistent methods of utilizing those specifications in law-making. Most of this independent material comes from Standards bodies. Their basic concept, the establishing of acceptable practice by prior agreement, is outlined, and the growth of the movement traced from the original development in Britain to a World-wide movement. Their processes of consultation and consensus represent a practical democratic system of self regulation. Studies of these aspects are rare, but a number of those relevant are reviewed, ranging from the Robens committee in Britain, through Building Code Reform in New Zealand, to a whole series of very recent reports from the United States, including a Presidential Task Force, an attempt to establish a National Standards Policy, a Federally commissioned study by a Professor of Law, and a Presidential Executive Order.From these emerge the pattern of complaint: Regulatory control is excessive, rigid, and liable to cause economic waste. It tends to be ineffective, and fails to achieve primary aims. As technology development exposes society to greater risks, efficiency becomes more vital, and failure to achieve control a serious danger. Problems arise from the failure of traditional legal approaches to adapt to the newer challenge of technology, particularly the legal acceptance of law "as it is" without recognition that the task calls for developing the law-making process to meet the needs of the changed situation. It is contended that many of the problems in regulatory control of technology come from the practice of making technical specification material direct legal command. The various reports reviewed comment on the limitations inherent in negative legislative control, the irrelevance of litigation, Court action and punishment, to the fundamental problem of achieving successful control. There is need for the encouragement of self regulation, and establishment of appropriate links with law.The special characteristics and responsibilities of law controlling technology are brought out, and call for identification as a separate branch of law: "Technological Law". Such law, it is contended, needs to make optimum usage of (a) the factors that have contributed to the dominance of technology, including the scientific approach, and the practice of prior agreement and (b) the essential components of democratic society, including participation, consensus, decentralized control, and self regulation associated with a formal method of determining acceptability.Practical proposals are developed involving the recognition of the practice of legislating by reference to independent technical specifications the encouragement of self-regulation processes through statutory backing, and their linking by recognition of the dyad in law, a separation of fundamental aims and principles appropriate to law from the means of meeting these aims.There is detailed examination of the three themes of reform. Techniques of the reference process, the legal objections, and the range of practices are examined, and acceptable technique suggested. The significance and importance of self-regulation is examined, and the contribution of "Standards" developed. A detailed examination is made of the various examples of two part law found in legislation, or in the studies reviewed. The framing of law in terms of general requirements is considered in relation to the problem of certainty and the idealization of the performance concept. The prerogative of the law-maker to designate certain practices as complying with general requirements is established as fundamental. The objection that this is a function of interpretation which lies exclusively with the Courts is discussed and the principle advanced that the vital Court function should never be called into the routine observance area.Technological law has as its essential aim the achievement of observance. Punishment, and court action is indication of failure. The emphasis must be on understanding and facilitating compliance. The second part of the dyad calls for sets of interrelated, interdependent specifications of acceptable practice, serving equally differing specialized laws, technical practices, commercial practices and education, and clarifying in positive fashion that which complies with law. The existing, established mechanisms of the world Standards movement are seen as providing the sets of technical specifications to fulfill this second function. This industry-developed process of self regulation utilises the techniques of prior agreement and in practical form, the elusive concept of consensus.Studies have emphasised the superior ability of the system to call in technical resources and voluntary effort to the service of law-making, in comparison with the resources of a governmental agency. The desirable aim is partnership, and the utilization of substantial measures of voluntary compliance.The question of recognition and authority for Standards and their producing organizations is seen as essential, and criteria are developed from the examples reviewed, notably from the pioneer New Zealand Act of 1941.The study emphasizes the little recognised function of Standards organizations of identifying acceptable practice, providing what has become an essential component of the machinery of government of a modern state.The mechanism provides a basis of certainty for commercial operations, and, through the strength of consumer or purchaser choice, an effective method of control as an alternative to yet more complex regulatory activity.

Over the last three centuries the rapidly increasing influence of technology has come to dominate every aspect of human life. Progressive realization of adverse effects has led to increasing demand for and imposition of control measures. The concept of common law embodied in legal tradition have been found inadequate, and forced a change to "enacted law". The regulatory explosion necessitated delegation from legislative to executive agencies.The resulting techniques of control developed in the United Kingdom, New Zealand, Australia, Canada and the United States are examined. One common factor stands out, the extensive dependence of law-making bodies on independent technical specification material from non-government sources, and the confused, conflicting, and inconsistent methods of utilizing those specifications in law-making. Most of this independent material comes from Standards bodies. Their basic concept, the establishing of acceptable practice by prior agreement, is outlined, and the growth of the movement traced from the original development in Britain to a World-wide movement. Their processes of consultation and consensus represent a practical democratic system of self regulation. Studies of these aspects are rare, but a number of those relevant are reviewed, ranging from the Robens committee in Britain, through Building Code Reform in New Zealand, to a whole series of very recent reports from the United States, including a Presidential Task Force, an attempt to establish a National Standards Policy, a Federally commissioned study by a Professor of Law, and a Presidential Executive Order.From these emerge the pattern of complaint: Regulatory control is excessive, rigid, and liable to cause economic waste. It tends to be ineffective, and fails to achieve primary aims. As technology development exposes society to greater risks, efficiency becomes more vital, and failure to achieve control a serious danger. Problems arise from the failure of traditional legal approaches to adapt to the newer challenge of technology, particularly the legal acceptance of law "as it is" without recognition that the task calls for developing the law-making process to meet the needs of the changed situation. It is contended that many of the problems in regulatory control of technology come from the practice of making technical specification material direct legal command. The various reports reviewed comment on the limitations inherent in negative legislative control, the irrelevance of litigation, Court action and punishment, to the fundamental problem of achieving successful control. There is need for the encouragement of self regulation, and establishment of appropriate links with law.The special characteristics and responsibilities of law controlling technology are brought out, and call for identification as a separate branch of law: "Technological Law". Such law, it is contended, needs to make optimum usage of (a) the factors that have contributed to the dominance of technology, including the scientific approach, and the practice of prior agreement and (b) the essential components of democratic society, including participation, consensus, decentralized control, and self regulation associated with a formal method of determining acceptability.Practical proposals are developed involving the recognition of the practice of legislating by reference to independent technical specifications the encouragement of self-regulation processes through statutory backing, and their linking by recognition of the dyad in law, a separation of fundamental aims and principles appropriate to law from the means of meeting these aims.There is detailed examination of the three themes of reform. Techniques of the reference process, the legal objections, and the range of practices are examined, and acceptable technique suggested. The significance and importance of self-regulation is examined, and the contribution of "Standards" developed. A detailed examination is made of the various examples of two part law found in legislation, or in the studies reviewed. The framing of law in terms of general requirements is considered in relation to the problem of certainty and the idealization of the performance concept. The prerogative of the law-maker to designate certain practices as complying with general requirements is established as fundamental. The objection that this is a function of interpretation which lies exclusively with the Courts is discussed and the principle advanced that the vital Court function should never be called into the routine observance area.Technological law has as its essential aim the achievement of observance. Punishment, and court action is indication of failure. The emphasis must be on understanding and facilitating compliance. The second part of the dyad calls for sets of interrelated, interdependent specifications of acceptable practice, serving equally differing specialized laws, technical practices, commercial practices and education, and clarifying in positive fashion that which complies with law. The existing, established mechanisms of the world Standards movement are seen as providing the sets of technical specifications to fulfill this second function. This industry-developed process of self regulation utilises the techniques of prior agreement and in practical form, the elusive concept of consensus.Studies have emphasised the superior ability of the system to call in technical resources and voluntary effort to the service of law-making, in comparison with the resources of a governmental agency. The desirable aim is partnership, and the utilization of substantial measures of voluntary compliance.The question of recognition and authority for Standards and their producing organizations is seen as essential, and criteria are developed from the examples reviewed, notably from the pioneer New Zealand Act of 1941.The study emphasizes the little recognised function of Standards organizations of identifying acceptable practice, providing what has become an essential component of the machinery of government of a modern state.The mechanism provides a basis of certainty for commercial operations, and, through the strength of consumer or purchaser choice, an effective method of control as an alternative to yet more complex regulatory activity.

Over the last three centuries the rapidly increasing influence of technology has come to dominate every aspect of human life. Progressive realization of adverse effects has led to increasing demand for and imposition of control measures. The concept of common law embodied in legal tradition have been found inadequate, and forced a change to "enacted law". The regulatory explosion necessitated delegation from legislative to executive agencies.The resulting techniques of control developed in the United Kingdom, New Zealand, Australia, Canada and the United States are examined. One common factor stands out, the extensive dependence of law-making bodies on independent technical specification material from non-government sources, and the confused, conflicting, and inconsistent methods of utilizing those specifications in law-making. Most of this independent material comes from Standards bodies. Their basic concept, the establishing of acceptable practice by prior agreement, is outlined, and the growth of the movement traced from the original development in Britain to a World-wide movement. Their processes of consultation and consensus represent a practical democratic system of self regulation. Studies of these aspects are rare, but a number of those relevant are reviewed, ranging from the Robens committee in Britain, through Building Code Reform in New Zealand, to a whole series of very recent reports from the United States, including a Presidential Task Force, an attempt to establish a National Standards Policy, a Federally commissioned study by a Professor of Law, and a Presidential Executive Order.From these emerge the pattern of complaint: Regulatory control is excessive, rigid, and liable to cause economic waste. It tends to be ineffective, and fails to achieve primary aims. As technology development exposes society to greater risks, efficiency becomes more vital, and failure to achieve control a serious danger. Problems arise from the failure of traditional legal approaches to adapt to the newer challenge of technology, particularly the legal acceptance of law "as it is" without recognition that the task calls for developing the law-making process to meet the needs of the changed situation. It is contended that many of the problems in regulatory control of technology come from the practice of making technical specification material direct legal command. The various reports reviewed comment on the limitations inherent in negative legislative control, the irrelevance of litigation, Court action and punishment, to the fundamental problem of achieving successful control. There is need for the encouragement of self regulation, and establishment of appropriate links with law.The special characteristics and responsibilities of law controlling technology are brought out, and call for identification as a separate branch of law: "Technological Law". Such law, it is contended, needs to make optimum usage of (a) the factors that have contributed to the dominance of technology, including the scientific approach, and the practice of prior agreement and (b) the essential components of democratic society, including participation, consensus, decentralized control, and self regulation associated with a formal method of determining acceptability.Practical proposals are developed involving the recognition of the practice of legislating by reference to independent technical specifications the encouragement of self-regulation processes through statutory backing, and their linking by recognition of the dyad in law, a separation of fundamental aims and principles appropriate to law from the means of meeting these aims.There is detailed examination of the three themes of reform. Techniques of the reference process, the legal objections, and the range of practices are examined, and acceptable technique suggested. The significance and importance of self-regulation is examined, and the contribution of "Standards" developed. A detailed examination is made of the various examples of two part law found in legislation, or in the studies reviewed. The framing of law in terms of general requirements is considered in relation to the problem of certainty and the idealization of the performance concept. The prerogative of the law-maker to designate certain practices as complying with general requirements is established as fundamental. The objection that this is a function of interpretation which lies exclusively with the Courts is discussed and the principle advanced that the vital Court function should never be called into the routine observance area.Technological law has as its essential aim the achievement of observance. Punishment, and court action is indication of failure. The emphasis must be on understanding and facilitating compliance. The second part of the dyad calls for sets of interrelated, interdependent specifications of acceptable practice, serving equally differing specialized laws, technical practices, commercial practices and education, and clarifying in positive fashion that which complies with law. The existing, established mechanisms of the world Standards movement are seen as providing the sets of technical specifications to fulfill this second function. This industry-developed process of self regulation utilises the techniques of prior agreement and in practical form, the elusive concept of consensus.Studies have emphasised the superior ability of the system to call in technical resources and voluntary effort to the service of law-making, in comparison with the resources of a governmental agency. The desirable aim is partnership, and the utilization of substantial measures of voluntary compliance.The question of recognition and authority for Standards and their producing organizations is seen as essential, and criteria are developed from the examples reviewed, notably from the pioneer New Zealand Act of 1941.The study emphasizes the little recognised function of Standards organizations of identifying acceptable practice, providing what has become an essential component of the machinery of government of a modern state.The mechanism provides a basis of certainty for commercial operations, and, through the strength of consumer or purchaser choice, an effective method of control as an alternative to yet more complex regulatory activity.

Over the last three centuries the rapidly increasing influence of technology has come to dominate every aspect of human life. Progressive realization of adverse effects has led to increasing demand for and imposition of control measures. The concept of common law embodied in legal tradition have been found inadequate, and forced a change to "enacted law". The regulatory explosion necessitated delegation from legislative to executive agencies.The resulting techniques of control developed in the United Kingdom, New Zealand, Australia, Canada and the United States are examined. One common factor stands out, the extensive dependence of law-making bodies on independent technical specification material from non-government sources, and the confused, conflicting, and inconsistent methods of utilizing those specifications in law-making. Most of this independent material comes from Standards bodies. Their basic concept, the establishing of acceptable practice by prior agreement, is outlined, and the growth of the movement traced from the original development in Britain to a World-wide movement. Their processes of consultation and consensus represent a practical democratic system of self regulation. Studies of these aspects are rare, but a number of those relevant are reviewed, ranging from the Robens committee in Britain, through Building Code Reform in New Zealand, to a whole series of very recent reports from the United States, including a Presidential Task Force, an attempt to establish a National Standards Policy, a Federally commissioned study by a Professor of Law, and a Presidential Executive Order.From these emerge the pattern of complaint: Regulatory control is excessive, rigid, and liable to cause economic waste. It tends to be ineffective, and fails to achieve primary aims. As technology development exposes society to greater risks, efficiency becomes more vital, and failure to achieve control a serious danger. Problems arise from the failure of traditional legal approaches to adapt to the newer challenge of technology, particularly the legal acceptance of law "as it is" without recognition that the task calls for developing the law-making process to meet the needs of the changed situation. It is contended that many of the problems in regulatory control of technology come from the practice of making technical specification material direct legal command. The various reports reviewed comment on the limitations inherent in negative legislative control, the irrelevance of litigation, Court action and punishment, to the fundamental problem of achieving successful control. There is need for the encouragement of self regulation, and establishment of appropriate links with law.The special characteristics and responsibilities of law controlling technology are brought out, and call for identification as a separate branch of law: "Technological Law". Such law, it is contended, needs to make optimum usage of (a) the factors that have contributed to the dominance of technology, including the scientific approach, and the practice of prior agreement and (b) the essential components of democratic society, including participation, consensus, decentralized control, and self regulation associated with a formal method of determining acceptability.Practical proposals are developed involving the recognition of the practice of legislating by reference to independent technical specifications the encouragement of self-regulation processes through statutory backing, and their linking by recognition of the dyad in law, a separation of fundamental aims and principles appropriate to law from the means of meeting these aims.There is detailed examination of the three themes of reform. Techniques of the reference process, the legal objections, and the range of practices are examined, and acceptable technique suggested. The significance and importance of self-regulation is examined, and the contribution of "Standards" developed. A detailed examination is made of the various examples of two part law found in legislation, or in the studies reviewed. The framing of law in terms of general requirements is considered in relation to the problem of certainty and the idealization of the performance concept. The prerogative of the law-maker to designate certain practices as complying with general requirements is established as fundamental. The objection that this is a function of interpretation which lies exclusively with the Courts is discussed and the principle advanced that the vital Court function should never be called into the routine observance area.Technological law has as its essential aim the achievement of observance. Punishment, and court action is indication of failure. The emphasis must be on understanding and facilitating compliance. The second part of the dyad calls for sets of interrelated, interdependent specifications of acceptable practice, serving equally differing specialized laws, technical practices, commercial practices and education, and clarifying in positive fashion that which complies with law. The existing, established mechanisms of the world Standards movement are seen as providing the sets of technical specifications to fulfill this second function. This industry-developed process of self regulation utilises the techniques of prior agreement and in practical form, the elusive concept of consensus.Studies have emphasised the superior ability of the system to call in technical resources and voluntary effort to the service of law-making, in comparison with the resources of a governmental agency. The desirable aim is partnership, and the utilization of substantial measures of voluntary compliance.The question of recognition and authority for Standards and their producing organizations is seen as essential, and criteria are developed from the examples reviewed, notably from the pioneer New Zealand Act of 1941.The study emphasizes the little recognised function of Standards organizations of identifying acceptable practice, providing what has become an essential component of the machinery of government of a modern state.The mechanism provides a basis of certainty for commercial operations, and, through the strength of consumer or purchaser choice, an effective method of control as an alternative to yet more complex regulatory activity.

Over the last three centuries the rapidly increasing influence of technology has come to dominate every aspect of human life. Progressive realization of adverse effects has led to increasing demand for and imposition of control measures. The concept of common law embodied in legal tradition have been found inadequate, and forced a change to "enacted law". The regulatory explosion necessitated delegation from legislative to executive agencies.The resulting techniques of control developed in the United Kingdom, New Zealand, Australia, Canada and the United States are examined. One common factor stands out, the extensive dependence of law-making bodies on independent technical specification material from non-government sources, and the confused, conflicting, and inconsistent methods of utilizing those specifications in law-making. Most of this independent material comes from Standards bodies. Their basic concept, the establishing of acceptable practice by prior agreement, is outlined, and the growth of the movement traced from the original development in Britain to a World-wide movement. Their processes of consultation and consensus represent a practical democratic system of self regulation. Studies of these aspects are rare, but a number of those relevant are reviewed, ranging from the Robens committee in Britain, through Building Code Reform in New Zealand, to a whole series of very recent reports from the United States, including a Presidential Task Force, an attempt to establish a National Standards Policy, a Federally commissioned study by a Professor of Law, and a Presidential Executive Order.From these emerge the pattern of complaint: Regulatory control is excessive, rigid, and liable to cause economic waste. It tends to be ineffective, and fails to achieve primary aims. As technology development exposes society to greater risks, efficiency becomes more vital, and failure to achieve control a serious danger. Problems arise from the failure of traditional legal approaches to adapt to the newer challenge of technology, particularly the legal acceptance of law "as it is" without recognition that the task calls for developing the law-making process to meet the needs of the changed situation. It is contended that many of the problems in regulatory control of technology come from the practice of making technical specification material direct legal command. The various reports reviewed comment on the limitations inherent in negative legislative control, the irrelevance of litigation, Court action and punishment, to the fundamental problem of achieving successful control. There is need for the encouragement of self regulation, and establishment of appropriate links with law.The special characteristics and responsibilities of law controlling technology are brought out, and call for identification as a separate branch of law: "Technological Law". Such law, it is contended, needs to make optimum usage of (a) the factors that have contributed to the dominance of technology, including the scientific approach, and the practice of prior agreement and (b) the essential components of democratic society, including participation, consensus, decentralized control, and self regulation associated with a formal method of determining acceptability.Practical proposals are developed involving the recognition of the practice of legislating by reference to independent technical specifications the encouragement of self-regulation processes through statutory backing, and their linking by recognition of the dyad in law, a separation of fundamental aims and principles appropriate to law from the means of meeting these aims.There is detailed examination of the three themes of reform. Techniques of the reference process, the legal objections, and the range of practices are examined, and acceptable technique suggested. The significance and importance of self-regulation is examined, and the contribution of "Standards" developed. A detailed examination is made of the various examples of two part law found in legislation, or in the studies reviewed. The framing of law in terms of general requirements is considered in relation to the problem of certainty and the idealization of the performance concept. The prerogative of the law-maker to designate certain practices as complying with general requirements is established as fundamental. The objection that this is a function of interpretation which lies exclusively with the Courts is discussed and the principle advanced that the vital Court function should never be called into the routine observance area.Technological law has as its essential aim the achievement of observance. Punishment, and court action is indication of failure. The emphasis must be on understanding and facilitating compliance. The second part of the dyad calls for sets of interrelated, interdependent specifications of acceptable practice, serving equally differing specialized laws, technical practices, commercial practices and education, and clarifying in positive fashion that which complies with law. The existing, established mechanisms of the world Standards movement are seen as providing the sets of technical specifications to fulfill this second function. This industry-developed process of self regulation utilises the techniques of prior agreement and in practical form, the elusive concept of consensus.Studies have emphasised the superior ability of the system to call in technical resources and voluntary effort to the service of law-making, in comparison with the resources of a governmental agency. The desirable aim is partnership, and the utilization of substantial measures of voluntary compliance.The question of recognition and authority for Standards and their producing organizations is seen as essential, and criteria are developed from the examples reviewed, notably from the pioneer New Zealand Act of 1941.The study emphasizes the little recognised function of Standards organizations of identifying acceptable practice, providing what has become an essential component of the machinery of government of a modern state.The mechanism provides a basis of certainty for commercial operations, and, through the strength of consumer or purchaser choice, an effective method of control as an alternative to yet more complex regulatory activity.

Master of Science / Department of Mechanical and Nuclear Engineering / Kirby S. Chapman / Oxides of nitrogen (NOx), carbon monoxide (CO) and other combustion by-products of gas turbines have long been identified as harmful atmospheric pollutants to the environment and humans. Various government agencies place restrictions on emissions and often require some sort of emissions monitoring even for new low emission gas turbines. Predicting actual emissions from operating parameters that affect the formation of pollutants, called parametric emissions monitoring system (PEMS), has potential economic advantages compared to a continuous emissions monitoring system (CEMS). The problem is that a simple applicable PEMS does not exist. During this study, a gas turbine combustor model applying first engineering principles was developed to predict the emission formation of NOx and CO in a gas turbine. The model is based on a lean-premixed combustor with a main and pilot burner including the function of a bleeding air valve. The model relies on ambient condition and load. The load is expressed as a percentage of the target speed of the gas producer turbine. Air flow and fuel flow for the main and pilot burner are calculated by the model based on the load through a set of measured input data for a specific gas turbine. To find the combustion temperature characteristics, the combustor is divided into several zones. The temperature for each zone is calculated by applying an energy balance. To predict NOx and CO, several correlations explored by various researchers are used and compared against each other, using the calculated temperatures, pressures and equivalence ratios. A comparison between collected emissions examples from a turbine test cell data spreadsheet and predicted emissions by the developed model under the same conditions show a highly accurate match for NOx emission at any load. Because of the high variation of CO at part load, the model predictions only match the CO data set at full load.

Master of Science / Department of Mechanical and Nuclear Engineering / Guoqiang Hu / In this thesis, several algorithms and experiments involving the control of robot formations are presented. The algorithms used were focused on decentralized control. The experiments were implemented on two different experimental testbeds consisting of teams of wheeled mobile robots. The robots used are described along with their sensors and supporting hardware. Also, there is a discussion of the programming framework used to build the control software. The first control algorithm and experiment uses a robust consensus tracking algorithm to control a formation of robots to track a desired trajectory. The robots must maintain the correct formation shape while the formation follows the trajectory. This task is complicated by limited communication between the robots, and disturbances applied to the information exchange. Additionally, only a subset of the robots have access to the reference trajectory. In the second experiment, the same algorithm was re-implemented in a decentralized way, which more effectively demonstrated the goals of the algorithm. The second algorithm involves controlling a formation of robots without a global reference frame. In order to accomplish this, the formation description is reformulated into variables describing the relative positions of the robots, and vision-based measurements are used for control. A homography-based technique is used to determine the relative positions of the robots using a single camera. Then a consensus tracking controller similar to the one used previously is used to distribute the measured information to all of the robots. This is done despite the fact that different parts of the information are measured by different agents.

Due to strong motivation to reduce costs and increase performances of stationary diesel after-treatment systems, computational modeling has become a necessary step in system design and improvement. A unique mixing duct typified by significant changes in scale and strong flow curvature was evaluated for its potential to improve flow distribution across the SCR catalyst inlet face. The flow dynamics were investigated with a steady three-dimensional turbulence model and detailed chemistry was studied separately using a one-dimensional channel reactive flow model. Aqueous urea injection was modeled using Discrete Phase Modeling. The mixing duct performance relative to reactor dimensions and engine loads is discussed. The Impact of injector positions was studied using massless particle tracking. A total of three geometries were evaluated using a Uniformity Index of the ammonia-to-NOx feed ratio. It was found that a higher mixing duct height to inlet diameter ratio yielded better mixing.

Due to strong motivation to reduce costs and increase performances of stationary diesel after-treatment systems, computational modeling has become a necessary step in system design and improvement. A unique mixing duct typified by significant changes in scale and strong flow curvature was evaluated for its potential to improve flow distribution across the SCR catalyst inlet face. The flow dynamics were investigated with a steady three-dimensional turbulence model and detailed chemistry was studied separately using a one-dimensional channel reactive flow model. Aqueous urea injection was modeled using Discrete Phase Modeling. The mixing duct performance relative to reactor dimensions and engine loads is discussed. The Impact of injector positions was studied using massless particle tracking. A total of three geometries were evaluated using a Uniformity Index of the ammonia-to-NOx feed ratio. It was found that a higher mixing duct height to inlet diameter ratio yielded better mixing.